At West Dean Gardens chilli seed is sown in February in a heated propagator set at 25C to ensure a long growing season, to allow the plants to mature and bear ripe fruit for our Chilli Fiesta in August. But you can also sow seed in March and if you are nervous of growing from seed you will find plenty of chilli plants for sale at garden centres, though the choice of varieties will be limited.
Once the seed has germinated we maintain a minimum temperature of 14-15C at night during spring for the development of the plants.
There are lots of sizes of pots and containers that are useful for raising chilli seeds; we find a 7cm diameter square pot ideal as over 250 plants are grown here which take up a lot of room on the propagation bench at a busy time of year.
Square pots make better use of the available space. Alternatively seed can be broadcast into shallow trays or into modules – the choice is yours and depends on whether you want a lot of different chillies or lots of the same chilli.
A fresh seed sowing compost is best for this process and it’s important to only use clean pots, because at 25C you might germinate diseases as well as seedlings if your pots and compost are not clean.
Air, light, pests, water and warmth
- Chilli plants need light and warmth to thrive and do very well in unheated glasshouses from mid-May onwards. As the young seedling develops light is the most important factor to consider. At West Dean our plants are spaced and re-spaced maybe three times so that light hits all the plant all of the time, which is important for a healthy development and stability.
- We’re guided by the prevailing outdoor night time temperature- when it starts remaining in double figures then there is no further need for additional heat to be supplied.
- Vent your glasshouse whenever possible on sunny days for fresh air and to allow natural predators of glasshouse pests to find their way indoors. This will help you combat unwanted pests like aphids which are the biggest nuisance on chillies particularly early in the season.
- A daily check will mean that you find the problem as soon as it appears, which is a good thing. Remove the aphids by washing them off with plain water (only use soapy water when the plant is older) or squashing them.
- Another hot tip is to water your plant well in the morning and if additional watering is required, make it early afternoon- remembering to water the compost only not the plant itself.
- Don’t water your plants at night and then close down your glasshouse as you will have created warm moist air which may act as a highway for fungal spores of diseases like botrytis that bedevil plants in unheated glasshouses as autumn approaches.
- For best results keep the soil warm. If the soil is warm enough they will grow well.
- If in doubt don’t water, watering can reduce the soil temperature and these plants are used to a little drought.
- Chillies are self-pollinating, but good ventilation will help improve fruit set. Hoverflies and other beneficial insects will also pollinate them.